Air Source Heat Pump (ASHP) Hacks & Mods - Page 5

Xringer · 07-18-11, 08:29 AM

Seems like heating hot water, a high capacity (and Fast) HX would be desirable.
Especially if you designed something along the lines of On-Demand domestic hot water.

For a pool? Maybe shooting for max BTU-per-watt used used would be smarter.
Letting the HP run for longer cycles, using lower power.
My guess is, a pool HP would run a LOT of hours, to over-come the heat losses..

launboy · 07-18-11, 03:19 PM

I do recognize the dangers of working with propane, but the unit will be outdoors, and I'd be extra carfeul knowing how dangerous it is. We use it alot for various things camping, including starting wet campfires with a weed burner torch. Works surprisingly well.

I do not have a mapp gas torch, brazing rod, guages, vacuum pump or any of that stuff unfortunately.

Xringer, to maintain 104* water temp a HP probably will run a long time, esp with the inefficiencies of my hottub. Its a above ground tub, dug into the ground, and plumbed 35' underground(above the frostline though). The pipes are wrapped in silver bubble rap but it didn't seem to do much. We attempted to keep it open one winter and the 120v resistance element ran continuously and still only managed an average of 96*F. We closed it halfway through the winter because of the power bill. I dont want to run it through the winter. This HP is basically just supplemental heat. Anytime the sun is out I have 120,000(what its rated at anyway, I know I get less) btu of solar heat from 3 2x20 panels on the garage. They have no problem heating it up in the day, but if we use the tub at night with no aux heat it cools off pretty quickly. It cools off muuuch slower with the resistance heat running but the way its wired I can only run the pump on low if the heaters on. My use for the HP is mainly to keep the tub warm while were using it, so if it runs continuously the whole time thats fine. It will also allow it to stay warm on cloudy days hopefully.

Adam

Xringer · 07-18-11, 05:01 PM

Do you ever get over-heating with the solar during the wintertime?
What's the max it ever gets up to with Solar?

It seems like solar collectors would be the idea way to heat a hot tub..
Put in enough sq ft to over-heat it during the day time, so you could jump
in at night after working all day..
During the daytime use, you could slow down the circulator pump a bit..?.

launboy · 07-19-11, 01:25 AM

Never tried heating it with solar in the winter. The tubes in the panels run horizontally so we drain them and blow them out in the fall so they don't freeze in the winter. (We're in Wisconsin). These are just basic pool plat panel collectors, like the ones shown here.

<-- thats a 4x20 but same design. Just a flat matt of tiny black plastic tubes that run from one end to the other. They work really well and are very cheap but unfortunately due to no glazing or anything any wind, or low ambient temps lower their output quickly. Originally these(we have 3) were bought to heat out 18' AG pool, then I added the hottub and plumbed it in as well. They work well for the pool, but are obviously much more then necessary for the tub. It'll raise the temp of the tub like 10* an hour on a sunny day if I remember right. I'm not sure how hot its actually ever gotten the water, but I know it was over 120* a few times on accident(thermometer stops at 120*) and I couldn't stick my hand in it.

Hopping in after a long day is wonderful though, I'm 18(heading off to college at the end of summer) so hottub parties are fun too. lol. The only problem is, you have maybe 20 min with the pumps and jets on before the water cools off to much. The cool air bubbles really suck the heat out. Which is where the HP comes in! to maintain that temp at least for a while longer.

Unfortunately the pump that runs the solar, is also the filtration pump, and is a 1HP single speed pump. Overkill for both the pool and normal filtration time for the hottub, but we got the pump and filter for $40 at a garage sale from a guy who took down his pool so I can't complain. What i could do, and am surprised I never thought of, is to open the bypass valve for the Solar manifold so the flow through the panels would be reduced and run all day. Normally I'd just shut off flow to the panels if it got to hot, or divert it to the pool if I was home and remembered.

This link shows the build progress of the hottub. It's stayed pretty much the same since I finished. launboy's Spa build (updated W/ Pics!) • Under Construction • Trouble Free Pool

Adam

Xringer · 07-19-11, 06:55 AM

Wow, that's quite a project you got going there Adam! You are very DIY for an 18 YO!

If that '1HP single speed pump' has the right type of motor, (asynchronous?),
it might be a good candidate for adding an electronic speed control.

The 1/2 HP motor on my old wood stove blower was very easy to control with a 1500w light dimmer..

Maybe like this?
Amazon.com: MLCS 9410 20-Amp Heavy Duty Router Speed Control: Home Improvement

AC_Hacker · 07-19-11, 09:38 AM

Quote:

Originally Posted by Xringer

If that '1HP single speed pump' has the right type of motor, (asynchronous?), it might be a good candidate for adding an electronic speed control.[/IMG]

If it were only that easy...

Xringer, you should try your router speed controller on your sump pump. I'm pretty sure that you have said that you have both...

I could really use a controller like that on my loop pump. Please help.

-AC_Hacker

launboy · 07-19-11, 09:12 PM

Quote:

Originally Posted by AC_Hacker

If it were only that easy...

Xringer, you should try your router speed controller on your sump pump. I'm pretty sure that you have said that you have both...

-AC_Hacker

Do you think it won't work? The way I'm reading your post it sounds like there's an unseen problem with this solution. If that would work, it would help a lot of people over on the pool forum, $35 controller is much cheaper then a variable speed pump!!

Thank you Xringer, I do do a lot of DIY because it interests me. When i was little i read/looked at pics of the remodeling How-to books my parents had instead of playing with hotwheels, etc, like most kids. I chose Knex over video games, and the very first thing I ever bought with saved up money was a Phantom Vacuum cleaner, $200!

Honestly, I just get bored. So I find a project! One year I hand dug a 2ft deep 17ft dia hole so our pool was deeper, next year I installed solar, which has undergone three reconfigurations in successive summers. I did the hottub, build the shed you can see in some pics, installed a Home theater in the basement(surround sound, projector, and screen), made a riding mower run on propane and various other random little things. At the moment I'm making a water cooled vest just cause it seems like a neat idea.

Adam

Acuario · 09-10-11, 09:24 AM

It's been a busy summer with work but now that winter is coming (albeit short and not for a couple of months) time to re-visit the heat pumps. The pool one hasn't changed at all - I guess it will all work ok when I plug it in. I've put up the website again at:
Pool heater using recycled air conditioner

I'm just planning to start improving/get working

the boiler pre-heater project - I'll keep you all posted!

Nigel

Geo NR Gee · 09-10-11, 09:55 AM

Nigel,
Have you figured out how much it saves you compared to other ways of heating the pool? I sure like the idea of using the air source heat pumps like you did. Putting one of those in my attic sure would have cooled it down in the summer.

Acuario · 09-10-11, 12:44 PM

I have no idea really. I tried heating with a 'modified' gas water heater, basically stacking 2 heat exchangers one on the top of the other.

It worked ok but I was getting through a 25Kg bottle of gas (at 14 euros a bottle) in 2 days. There was a lot of waste heat that was unrecoverable and, although it helped heating, it wasn't really enough to enable the pool to be used all year.

I also tried with a dual skin steel vessel I have, feeding it with waste from the garden, olive, carob and almond branches etc. but again it helped but not enough and it's a real killer of a job as you have to continually feed it.

The heat pump is far superior in it's operation and almost no lost heat. I don't have to run them all day, just 2 - 3 hours a day (around 2 - 3 euros in electric) was enough after the water was up to temperature. I'll know more this year as the pool is now at the correct temperature so it's a maintenance task rather than a heat from cold task as it was last year.

07-18-11, 08:29 AM	#41
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Seems like heating hot water, a high capacity (and Fast) HX would be desirable. Especially if you designed something along the lines of On-Demand domestic hot water. For a pool? Maybe shooting for max BTU-per-watt used used would be smarter. Letting the HP run for longer cycles, using lower power. My guess is, a pool HP would run a LOT of hours, to over-come the heat losses..

07-18-11, 03:19 PM	#42
launboy Apprentice EcoRenovator Join Date: Mar 2011 Location: SE Wisconin Posts: 107 Thanks: 3 Thanked 11 Times in 9 Posts	I do recognize the dangers of working with propane, but the unit will be outdoors, and I'd be extra carfeul knowing how dangerous it is. We use it alot for various things camping, including starting wet campfires with a weed burner torch. Works surprisingly well. I do not have a mapp gas torch, brazing rod, guages, vacuum pump or any of that stuff unfortunately. Xringer, to maintain 104* water temp a HP probably will run a long time, esp with the inefficiencies of my hottub. Its a above ground tub, dug into the ground, and plumbed 35' underground(above the frostline though). The pipes are wrapped in silver bubble rap but it didn't seem to do much. We attempted to keep it open one winter and the 120v resistance element ran continuously and still only managed an average of 96*F. We closed it halfway through the winter because of the power bill. I dont want to run it through the winter. This HP is basically just supplemental heat. Anytime the sun is out I have 120,000(what its rated at anyway, I know I get less) btu of solar heat from 3 2x20 panels on the garage. They have no problem heating it up in the day, but if we use the tub at night with no aux heat it cools off pretty quickly. It cools off muuuch slower with the resistance heat running but the way its wired I can only run the pump on low if the heaters on. My use for the HP is mainly to keep the tub warm while were using it, so if it runs continuously the whole time thats fine. It will also allow it to stay warm on cloudy days hopefully. Adam

07-18-11, 05:01 PM	#43
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Do you ever get over-heating with the solar during the wintertime? What's the max it ever gets up to with Solar? It seems like solar collectors would be the idea way to heat a hot tub.. Put in enough sq ft to over-heat it during the day time, so you could jump in at night after working all day.. During the daytime use, you could slow down the circulator pump a bit..?.

07-19-11, 01:25 AM	#44
launboy Apprentice EcoRenovator Join Date: Mar 2011 Location: SE Wisconin Posts: 107 Thanks: 3 Thanked 11 Times in 9 Posts	Never tried heating it with solar in the winter. The tubes in the panels run horizontally so we drain them and blow them out in the fall so they don't freeze in the winter. (We're in Wisconsin). These are just basic pool plat panel collectors, like the ones shown here. <-- thats a 4x20 but same design. Just a flat matt of tiny black plastic tubes that run from one end to the other. They work really well and are very cheap but unfortunately due to no glazing or anything any wind, or low ambient temps lower their output quickly. Originally these(we have 3) were bought to heat out 18' AG pool, then I added the hottub and plumbed it in as well. They work well for the pool, but are obviously much more then necessary for the tub. It'll raise the temp of the tub like 10* an hour on a sunny day if I remember right. I'm not sure how hot its actually ever gotten the water, but I know it was over 120* a few times on accident(thermometer stops at 120*) and I couldn't stick my hand in it. Hopping in after a long day is wonderful though, I'm 18(heading off to college at the end of summer) so hottub parties are fun too. lol. The only problem is, you have maybe 20 min with the pumps and jets on before the water cools off to much. The cool air bubbles really suck the heat out. Which is where the HP comes in! to maintain that temp at least for a while longer. Unfortunately the pump that runs the solar, is also the filtration pump, and is a 1HP single speed pump. Overkill for both the pool and normal filtration time for the hottub, but we got the pump and filter for $40 at a garage sale from a guy who took down his pool so I can't complain. What i could do, and am surprised I never thought of, is to open the bypass valve for the Solar manifold so the flow through the panels would be reduced and run all day. Normally I'd just shut off flow to the panels if it got to hot, or divert it to the pool if I was home and remembered. This link shows the build progress of the hottub. It's stayed pretty much the same since I finished. launboy's Spa build (updated W/ Pics!) • Under Construction • Trouble Free Pool Adam

07-19-11, 06:55 AM	#45
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Wow, that's quite a project you got going there Adam! You are very DIY for an 18 YO! If that '1HP single speed pump' has the right type of motor, (asynchronous?), it might be a good candidate for adding an electronic speed control. The 1/2 HP motor on my old wood stove blower was very easy to control with a 1500w light dimmer.. Maybe like this? Amazon.com: MLCS 9410 20-Amp Heavy Duty Router Speed Control: Home Improvement

09-10-11, 09:24 AM	#48
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	It's been a busy summer with work but now that winter is coming (albeit short and not for a couple of months) time to re-visit the heat pumps. The pool one hasn't changed at all - I guess it will all work ok when I plug it in. I've put up the website again at: Pool heater using recycled air conditioner I'm just planning to start improving/get working the boiler pre-heater project - I'll keep you all posted! Nigel

09-10-11, 09:55 AM	#49
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Nigel, Have you figured out how much it saves you compared to other ways of heating the pool? I sure like the idea of using the air source heat pumps like you did. Putting one of those in my attic sure would have cooled it down in the summer.

09-10-11, 12:44 PM	#50
Acuario Apprentice EcoRenovator Join Date: May 2011 Location: Tortosa, Spain Posts: 221 Thanks: 2 Thanked 81 Times in 46 Posts	I have no idea really. I tried heating with a 'modified' gas water heater, basically stacking 2 heat exchangers one on the top of the other. It worked ok but I was getting through a 25Kg bottle of gas (at 14 euros a bottle) in 2 days. There was a lot of waste heat that was unrecoverable and, although it helped heating, it wasn't really enough to enable the pool to be used all year. I also tried with a dual skin steel vessel I have, feeding it with waste from the garden, olive, carob and almond branches etc. but again it helped but not enough and it's a real killer of a job as you have to continually feed it. The heat pump is far superior in it's operation and almost no lost heat. I don't have to run them all day, just 2 - 3 hours a day (around 2 - 3 euros in electric) was enough after the water was up to temperature. I'll know more this year as the pool is now at the correct temperature so it's a maintenance task rather than a heat from cold task as it was last year.